Ann Thorac Surg 2000;69:1940-1941
© 2000 The Society of Thoracic Surgeons
Case reports
Acute type A aortic dissection: retrograde perfusion with left superior vena cava
Charles R. Bridges, MD, ScDa,
Robert C. Gorman, MDa,
Mark M. Stecker, MD, PhDa,
Joseph E. Bavaria, MDa
a Division of Cardiothoracic Surgery, Department of Neurology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, USA
Address reprint requests to Dr Bridges, Department of Surgery, University of Pennsylvania Medical Center, 4 Silverstein, 3400 Spruce St, Philadelphia, PA 19104
e-mail: cbridges{at}mail.med.upenn.edu
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Abstract
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Retrograde cerebral perfusion with hypothermic circulatory arrest confers additional cerebral protection during repair of type A aortic dissection. We present a 42-year-old man with acute type A aortic dissection and a persistent, left superior vena cava. Cannulation of the right and left superior vena cava is used for retrograde perfusion of both hemispheres with bilateral monitoring of electroencephalogram and somatosensory-evoked potentials during and after the hypothermic circulatory arrest interval.
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Introduction
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Repair of acute type A aortic dissection can be accomplished with a variety of circulatory management protocols including hypothermic circulatory arrest (HCA), selective cerebral perfusion, and HCA combined with retrograde cerebral perfusion (RCP). Recent reports indicate significantly improved stroke and mortality rates when RCP is combined with HCA compared with HCA alone [1, 2].
A 42-year-old male presented with acute onset of back and anterior chest pain. A computed tomography scan showed a 5.5-cm dilatation of the ascending aorta. A magnetic resonance imaging of the chest revealed a type A dissection with an intimal flap arising at the aortic valve plane, extending into the descending thoracic aorta.
Physical examination revealed a healthy-appearing man with a blood pressure of 180/110 mm Hg, heart rate of 90 beats per minute, and respiratory rate of 20 per minute. His cardiac exam revealed a soft aortic insufficiency murmur. His abdominal exam was benign. There was no blood pressure differential in the arms, and his peripheral pulses were symmetric. His neurologic exam was nonfocal.
He was treated with esmolol and nitroprusside and transferred to the operating room. A transesophageal echocardiography (TEE) revealed trace mitral regurgitation, mild aortic regurgitation, and a type A aortic dissection beginning just above the aortic valve annulus extending distally. There was no carotid dissection. Flow in the right and left proximal coronary arteries was intact.
The sternum was divided. Heparin was administered, and the right femoral artery was cannulated. A 28F, right-angle venous cannula was passed retrograde into the proximal right superior vena cava (RSVC). A two-stage venous cannula was placed into the right atrial appendage and connected via a Y connector to the cannula from the RSVC and to the venous limb of the cardiopulmonary bypass circuit. The patient was cooled to a nasopharyngeal temperature of 18°C. During cooling, it was noted that the innominate vein was absent. A left superior vena cava (LSVC), which appeared to drain into the coronary sinus, was identified. The LSVC was cannulated retrograde using a 26F right-angle cannula. Snares were placed around both RSVC and LSVC cannulas. Cardiopulmonary bypass was interrupted momentarily while the LSVC and RSVC cannulas were connected to a common venous limb of the cardiopulmonary bypass circuit. Circulation was arrested at the appropriate time, and oxygenated blood at approximately 12°C was pumped retrograde into the RSVC and LSVC. A perfusion pressure of 20 mm Hg was maintained, with a flow of approximately 300 mL/min. A hemiarch replacement was performed using a 26F Dacron graft. Antegrade aortic arterial flow and rewarming were instituted via the graft after deairing. A cross-clamp was placed proximal to the anastomosis of the graft with the aortic arch. Proximal aortic root reconstruction was completed with resuspension of the aortic valve, and replacement of the ascending aorta with a 26F Dacron graft. A graft-to-graft anastomosis was performed and the patient was weaned from cardiopulmonary bypass. The postoperative TEE revealed no valvular regurgitation, with normal left ventricular function.
Figure 1 represents changes in electroencephalogram (EEG) and somatosensory evoked potentials (SEP) during the surgical procedure. In Figure 1B, a decrease in the frequency of the EEG signals is apparent and symmetric bilaterally. Also, a decrease in the amplitude of the SEP for the left and right median nerve is apparent during cooling. In Figure 1C, during rewarming, the EEG in the left and right hemispheres, as well as the SEP from the left and right sides, are symmetric and returning toward baseline.
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Fig 1. Changes in EEG and SEPs during surgery. The left side depicts EEG recordings from the left and right brain hemispheres. The right-sided waveforms represent somatosensory-evoked potentials for the left and right median nerve. The recording times are: (A) baseline recordings; (B) recordings during cooling; and (C) recordings during rewarming.
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The patient was extubated on the first postoperative day. He continued to make excellent progress and was discharged to home on the fifth postoperative day in excellent condition with no neurologic deficit.
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Comment
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A persistent LSVC occurs in up to 0.5% of the normal population [3]. Upon discovery of the persistent LSVC during cooling, several alternative approaches were available: ligation of the LSVC; simple clamping of the LSVC during the RCP interval; cannulation of the LSVC with retrograde perfusion; or no modification of the RCP protocol. In cases of coronary sinus ostial atresia, ligation of the LSVC can lead to myocardial ischemia and necrosis [4–6]. This rare anomaly was unlikely to be present in this patient, however, because the coronary sinus was cannulated for the administration of retrograde cardioplegia during the cross-clamp interval. Furthermore, in cases of coronary sinus ostial atresia, an innominate vein is usually present [4–6]. Also, ligation of the LSVC in the absence of a bridging innominate vein, as in this case, can lead to venous hypertension of the left upper extremity or an elevation in intracranial pressure [7]. The latter would be particularly undesirable because when combined with HCA, further exacerbation of postoperative cerebral dysfunction would be likely. Clamping of the LSVC during the RCP interval avoids these potential difficulties. However, simple clamping of the LSVC might result in preferential retrograde perfusion of the right hemisphere with suboptimal retrograde perfusion of the left hemisphere. Nonuniform cooling and perfusion of the left hemisphere during the RCP interval might then ensue. Finally, no modification of the RCP protocol might result in venous shunting.
Therefore, in the presence of a persistent LSVC, when RCP is indicated, cannulation of the LSVC with retrograde perfusion via the LSVC and RSVC is recommended, as performed in this case. Alternatively, if a bridging innominate vein is present, simple clamping of the LSVC during the RCP interval should be sufficient.
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References
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Bavaria J.E., Woo Y.J., Hall R.A., Wahl P.M., Acker M.A., Gardner T.J. Circulatory management with retrograde cerebral perfusion for acute Type A aortic dissection. Circulation 1996;94(Suppl):II173-II176.
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Bavaria J.E., Woo Y.J., Hall R.A., Carpenter J.P., Gardner T.J. Retrograde cerebral and distal aortic perfusion during ascending and thoracoabdominal aortic operations. Ann Thorac Surg 1995;60:345-353.[Abstract/Free Full Text]
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Bunger P.C., Neufeld D.A., Moore J.C., Carter G.A. Persistent left superior vena cava and associated structural and functional considerations. Angiology 1981;32:601-608.
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Muster A.J., Naheed Z.J., Backer C.L., Mavroudis C. Is surgical ligation of an accessory left superior vena cava always safe?. Pediatr Cardiol 1998;19:352-354.[Medline]
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Santoscoy R., Walters H.L., III, Ross R.D., Lyons J.M., Hakimi M. Coronary sinus ostial atresia with persistent left superior vena cava. Ann Thorac Surg 1996;61:879-882.[Abstract/Free Full Text]
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Yokota M., Kyoku I., Kitano M., et al. Atresia of the coronary sinus orifice. Fatal outcome after intraoperative division of the drainage left superior vena cava. J Thorac Cardiovasc Surg 1989;98:30-32.[Abstract]
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Inaoka M., Takagi N., Urita R., Hasegawa T. A case of pure unroofed coronary sinus syndrome with persistent left superior vena cava. Jpn J Thorac Surg 1992;45:463-466.
Accepted for publication November 5, 1999.
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Abstract
Introduction
